Processing and properties of SiC/vinyl ester nanocomposites

Abstract

The feasibility of improving polymer composites was investigated using 30 nm SiC nanoparticles in a vinyl ester resin. Even when the particle loading was less than 4% by weight, the viscosity of the nanoparticle suspension was found to increase much higher than that of microparticle suspension. This phenomenon may be the result of association between nanoparticles and polymer molecules, effectively making the nanoparticles larger. The resulting reduction in the mobility of polymer molecules also led to delayed curing. Ultrasonic mixing did not fully disperse the particles. As a result, the composite strength did not improve although the modulus increased. The use of a dispersant, methacryloxy propyl trimethoxy silane (MPS), improved the dispersion quality and hence the composite strength. The paper discusses the issues involved with processing, characterization and properties of SiC/vinyl ester nanocomposites. Methods of improving the nanocomposite quality are proposed in the paper as well.

Monodisperse SiC/vinyl ester nanocomposites: Dispersant formulation, synthesis, and characterization

“…3,7 Water increases one particle surface's affinity for another, which excludes organic molecules within agglomerates. Furthermore, water is difficult to remove from particle surfaces once these are immersed in organic liquids, as illustrated by the considerably higher heat of wetting by water compared to organic liquids.…”

“…Chain length is a factor in dispersion and a separation of 20-60 nm is necessary to overcome the van der Waals forces for colloid stability. 3,8 The eight carbon rule (oleophilic-hydrophilic balance point) was used as the guideline to achieve the particle-particle separation. A dispersant "hydroxypropyl methacrylate" with an alcohol head group -OH acting as a Lewis base was also selected as a test vehicle.…”

“…Therefore, a monolayer coverage dosage (m f ) of 62 fractional wt% of the mono-2-(methacryloyloxy)ethyl succinate (wt% dispersant/wt% SiC) was used to attain the minimum filled resin viscosity. 3,6 Similarly, the dosage of hydroxypropyl methacrylate with a molar mass of 144.17/1000 kg mol À1 was determined to be 39 fractional wt%.…”

“…1 However, the degree of enhancement of a particular property is highly dependent on the filler/matrix material system used, the filler/ matrix interfacial bonding, and the state of dispersion of the filler throughout the matrix. 2,3 A good dispersion of nanofiller in the polymer matrix coupling with a strong interface between the two phases is essential to achieve enhanced mechanical properties. 4,5 Covalent ceramic materials like silicon carbide (SiC) have been recognized as potential candidates for structural applications because of their superior mechanical properties (strength, stiffness, and hardness), chemical inertness (oxidation and corrosion resistance), and thermal stability at high temperatures.…”

Development Of Multistitched Three-Dimensional (3D) Nanocomposite And Evaluation Of Its Mechanical And Impact Properties

“…The modulus of the composite increased by adding silicon carbide (SiC) nanoparticles regardless of the dispersion quality, whereas strength was highly sensitive to dispersion quality and increased with the addition of the coupling agent and dispersant. Hence, a well-dispersed SiC was required to improve the quality of the nanocomposite [14]. In addition, the tensile strength of the E-glass/unsaturated isophthalic polyester composite decreased by increasing the SiC particle.…”